【正确答案】 B

【答案解析】[解析] A run-on sentence is a sentence in which two or more independent clauses(that is，complete sentences)are joined with no punctuation or conjunction. run-on sentence流水句；溶合句；不间断句子；缺乏连接词或标点符号的长句。很明显这里Rice called Afghanistan an "important test of the credibility of NATO" 和President Barrack Obama made the same claim in late 2009 when he announced his decision之间缺少一定的连接词和标点符号。